Open Microscopy Environment

We have some images uploaded (.dm3 and .tiff) to OMERO. On some clients, the image thumbnails appear black, and when you double-click on the thumbnail, the following message appears: The image could not be opened. The image is not a valid image. However, on other clients, the images appear normal. Is there some client-side issue? Both clients are mac. We are using omero4.2. Any ideas are appreciated.

The "omeroinsight.log" from the "omero/log" directory of the home directory on the client would be very helpful on any of these machines.

On Windows:

C:\Documents and Settings\<username>\omero\log\

On Mac OS X:

/Users/<username>/omero/log/